Focus detection device for a camera

Abstract

A focus detection device for a camera capable of detecting focuses at a plurality of areas on a photographing field, comprises two pairs of photo-electric conversion device arrays arranged on one substrate in optical correspondence to two of said plurality of areas; the two areas being arranged on a line extending generally vertically to a horizontal center axis crossing an optical line on the photographing field, on the opposite sides of the center line; and a refocusing optical system for refocusing light beams passing through different points of an exit pupil of a photographing lens, onto the two pairs of photo-electric conversion device arrays; the refocusing optical system including a pair of refocusing lenses for focusing the light beams onto the two pairs of photo-electric conversion device arrays.

What is claimed is: 
     
       1. A focus detection device for a camera capable of detecting focuses at a plurality of areas on a photographing field, comprising: two pairs of photo-electric conversion device arrays arranged on one substrate in optical correspondence to two of said plurality of areas;   said two areas being arranged on a line extending generally vertically to a center axis crossing an optical axis on said photographing field, on opposite sides of said center line; and   a refocusing optical system for refocusing light beams passing through different points of an exit pupil of a photographing lens, onto said two pairs of photo-electric conversion device arrays;   said refocusing optical system including one pair of refocusing lenses for refocusing light beams onto both of said two pairs of photo-electric conversion device arrays.   
     
     
       2. A focus detection device for a camera according to claim 1, further comprising another two pairs of photo-electric conversion device arrays and another pair of refocusing lenses for refocusing light beams onto both of said other two pairs of photo-electric conversion device arrays, wherein the four pairs of photo-electric conversion device arrays are arranged in the vicinities of four points dividing each of crossing diagonal lines of the photographing field into three equal parts. 
     
     
       3. A focus detection device of a camera according to claim 1 wherein the photographing field is rectangular and the center line crossing the optical axis on the photographing field is a horizontal line with the camera oriented so that the length of the photographing field is horizontal. 
     
     
       4. A focus detection device for a camera according to claim 1 wherein said photo-electric conversion device arrays are one dimensional photo-electric conversion device arrays. 
     
     
       5. A focus detection device for a camera according to claim 1 wherein said two areas are arranged on a line offset horizontally from said optical axis. 
     
     
       6. In a focus detection device for a camera including a photo-electric conversion device array to detect focusing states at a plurality of areas in a photographing field having a horizontal center line crossing an optical axis, the improvement wherein two of said plurality of areas are elongated along a length of each and are arranged with the length on a perpendicular line offset from the optical axis along the horizontal center line and extending substantially perpendicularly to the horizontal center line. 
     
     
       7. A focus detection device for a camera according to claim 6, wherein four areas including two more areas are arranged in the vicinities of four points dividing each of crossing diagonal lines of the photographing field into three equal parts. 
     
     
       8. A focus detection device for a camera according to claim 6, wherein another of said plurality of areas is an area including a central point of the photographing field. 
     
     
       9. A focus detection device for a camera capable of detecting focusing states at a plurality of areas on a photographing field, comprising: two pairs of photo-electric conversion device arrays arranged on one substrate and optically corresponding to two of said plurality of areas, respectively, the photo-electric conversion device arrays of each pair being arranged alternately with the photo-electric conversion device arrays of the other pair on a single line, and said two areas being arranged on a line that is offset from an optical axis of the photographing field and that is substantially perpendicular to a center line of the photographing field crossing the optical axis; and   a refocusing optical system for refocusing light beams passing through different portions of an exit pupil of a photographing lens onto said two pairs of photo-electric conversion device arrays, said refocusing optical system including one pair of refocusing lenses for refocusing light beams onto both of said two pairs of photo-electric conversion device arrays.   
     
     
       10. A focus detection device for a camera according to claim 9 further comprising another two pairs of photo-electric conversion device arrays and another pair of refocusing lenses for refocusing light beams onto both of said another two pairs of photo-electric conversion device arrays, wherein the four pairs of photo-electric conversion device arrays are arranged in the vicinities of four points dividing each of crossing diagonal lines of the photographing field into three equal parts. 
     
     
       11. A focus detection device of a camera according to claim 9 wherein the photographing field is rectangular and the center line crossing the optical axis on the photographing field is a horizontal line with the camera oriented so that the length of the photographing field is horizontal. 
     
     
       12. A focus detection device for a camera according to claim 9 wherein said photo-electric conversion device arrays are one dimensional photo-electric conversion device arrays. 
     
     
       13. A focus detection device for a camera according to claim 9 wherein said two areas are arranged on a line offset horizontally from said optical axis.